1. Field
The present invention relates to a transmission assembly, and more particularly to a magnetic transmission assembly.
2. Related Art
A transmission device not only can be used for power transmission and delivery, but also has the function of accelerating or decelerating the rotation of a power source. Transmission devices applied in conventional automobile engines include mechanical and hydraulic gear boxes. Magnetic transmission devices are applied in electric or hybrid automobiles.
For technologies of variable speed motors, reference is made to U.S. Pat. No. 3,980,937 entitled “Fractional Horsepower Gear Motor” issued on Sep. 14, 1976, in which a power output by a motor is transmitted through a mechanical gear assembly so as to achieve torque conversion and transmission.
In addition, U.S. Pat. No. 5,825,111 entitled “Single-phase induction motor 4/6 pole common winding connection with magnetic motive force symmetrically distributed” issued on Dec. 20, 1998, and U.S. Pat. No. 7,598,648 entitled “2/6 pole single-phase induction motor having shared windings” issued on Dec. 6, 2009, disclose methods of achieving variable speed transmission by changing the number of poles of a stator of a induction motor.
For technologies related to magnetic transmission device, reference is made to an article “A Novel High-Performance Magnetic Gear” (IEEE Transactions on Magnetics, Vol. 37, No. 4, July, 2001) by K. Atallah and D. Howe.
The mechanical transmission device has disadvantages of high noise level and heavy weight. Although the ordinary magnetic transmission device has reduced vibration and noise level, its weight also cannot be reduced. Moreover, when applied in an electric automobile, an electric motor not only needs to meet the requirements of different output torques and travel speeds, but also needs to meet the requirements of high performance operation. Accordingly, the motor is usually combined with a transmission device. In such a combination, it is quite difficult to improve the overall drive power density of the motor and the transmission device (due that the total weight of the motor and the transmission device is heavy).